There is an environment where a plurality of computer-related devices can communicate with a common device via a wired or wireless network. In the specification, the “computer-related device” includes all types of electrical appliances that implement given functions by use of a computer. Specifically, the computer-related device includes digital home electrical appliances such as personal computers and television sets but is not limited thereto.
An example of a device used in this kind of communication environment includes NAS (network-attached storage). JP-A-2004-151824 describes an example of technique constituting the network including such an NAS. The entirety of the publication is incorporated herein by reference.
Generally, the NAS includes a data-recordable hard disk and a motor for driving the hard disk. The motor is driven by electric power supplied from a power source.
In general, there is a need for a power saved and/or silenced device by reducing wasteful operations of the device, regardless of the environment in which the device is used. The environment includes: an environment in which a plurality of computer-related devices communicate with the device (a common device) via a wired or wireless network (hereinafter referred to as a “network-connected environment”) or an environment where each of the computer-related devices individually and directly connected to corresponding one of the devices (hereinafter referred to as an “individually-connected environment”).
For example, when the device is the NAS including a cooling fan for cooling the motor, reduction of wasteful operations leads to not only a reduction in power consumption but also silencing due to the reduction of wasteful operations of the cooling fan.
When the device is used in the individually-connected environment, power of the device can be appropriately management by monitoring the state (an operative state or an inoperative state) of the corresponding computer-related device and controlling the power state of the device in response to the monitored results.
However, when the device is used in the network-connected environment, the device is shared by a plurality of computer-related device. Therefore, the appropriate power management of the device used in the network-connected environment is hardly realized by only a technique employed in the individually-connected environment.